Improved color demosaicking in weak spectral correlation

Abstract

Almost all existing color demosaicking algorithms for digital cameras are designed on the assumption of high correlation between red, green, blue (or some other primary color) bands. They exploit spectral correlations between the primary color bands to interpolate the missing color samples. The interpolation errors increase in areas of no or weak spectral correlations. Consequently, objectionable artifacts tend to occur on highly saturated colors and in the presence of large sensor noises, whenever the assumption of high spectral correlations does not hold. This paper proposes a remedy to the above problem that has long been overlooked in the literature. The main contribution of this work is a technique of correcting the interpolation errors of any existing color demosaicking algorithm by piecewise autoregressive modeling.